refactor(tests): compute project root once in bootstrap

Address review feedback (Copilot) on the standalone bootstrap: the
project root was computed twice -- once inline for $buildScript and again
a few lines later for $projectRoot -- which is exactly the kind of
duplication that can drift. Hoist the single $projectRoot assignment
above the BHBuildOutput guard and derive $buildScript from it via
Join-Path, in Manifest.tests.ps1 (both blocks) and the tests/Unit/
Private and Public templates.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: tablackburn

tests/Manifest.tests.ps1

@@ -57,6 +57,10 @@
 param()
 
 BeforeDiscovery {
+    # Resolve the project root once (tests/ -> repo root); used both to locate
+    # build.ps1 below and to compute the staged build output path.
+    $projectRoot = Split-Path -Path $PSScriptRoot -Parent
+
     # Check if the BHBuildOutput environment variable exists to determine if this test is running in a psake
     # build or not. If it does not exist, it is not running in a psake build, so build the module.
     if ($null -eq $Env:BHBuildOutput) {
@@ -67,12 +71,11 @@ BeforeDiscovery {
         # Invoke with & (not dot-sourcing): build.ps1 ends in an exit statement, and
         # the call operator contains it to the script boundary instead of ending the
         # whole Pester run.
-        $buildScript = Join-Path -Path (Split-Path -Path $PSScriptRoot -Parent) -ChildPath 'build.ps1'
+        $buildScript = Join-Path -Path $projectRoot -ChildPath 'build.ps1'
         & $buildScript -Task 'Build' -Bootstrap
     }
 
     # PowerShellBuild outputs to Output/<ModuleName>/<Version>/, override BHBuildOutput
-    $projectRoot = Split-Path -Path $PSScriptRoot -Parent
     $sourceManifest = Join-Path -Path $projectRoot -ChildPath "$Env:BHProjectName/$Env:BHProjectName.psd1"
     $moduleVersion = (Import-PowerShellDataFile $sourceManifest).ModuleVersion
     $Env:BHBuildOutput = Join-Path -Path $projectRoot -ChildPath "Output/$Env:BHProjectName/$moduleVersion"
@@ -99,6 +102,10 @@ BeforeDiscovery {
     $isTemplate = Test-Path -LiteralPath (Join-Path -Path $Env:BHProjectPath -ChildPath 'CHANGELOG.template.md')
 }
 BeforeAll {
+    # Resolve the project root once (tests/ -> repo root); used both to locate
+    # build.ps1 below and to compute the staged build output path.
+    $projectRoot = Split-Path -Path $PSScriptRoot -Parent
+
     # Check if the BHBuildOutput environment variable exists to determine if this test is running in a psake
     # build or not. If it does not exist, it is not running in a psake build, so build the module.
     if ($null -eq $Env:BHBuildOutput) {
@@ -109,12 +116,11 @@ BeforeAll {
         # Invoke with & (not dot-sourcing): build.ps1 ends in an exit statement, and
         # the call operator contains it to the script boundary instead of ending the
         # whole Pester run.
-        $buildScript = Join-Path -Path (Split-Path -Path $PSScriptRoot -Parent) -ChildPath 'build.ps1'
+        $buildScript = Join-Path -Path $projectRoot -ChildPath 'build.ps1'
         & $buildScript -Task 'Build' -Bootstrap
     }
 
     # PowerShellBuild outputs to Output/<ModuleName>/<Version>/, override BHBuildOutput
-    $projectRoot = Split-Path -Path $PSScriptRoot -Parent
     $sourceManifest = Join-Path -Path $projectRoot -ChildPath "$Env:BHProjectName/$Env:BHProjectName.psd1"
     $moduleVersion = (Import-PowerShellDataFile $sourceManifest).ModuleVersion
     $Env:BHBuildOutput = Join-Path -Path $projectRoot -ChildPath "Output/$Env:BHProjectName/$moduleVersion"

tests/Unit/Private/Invoke-{{Prefix}}Helper.tests.ps1

@@ -6,6 +6,10 @@
 param()
 
 BeforeDiscovery {
+    # Resolve the project root once (tests/Unit/<Layer>/ -> repo root, three levels up);
+    # used both to locate build.ps1 below and to compute the staged build output path.
+    $projectRoot = Split-Path -Path (Split-Path -Path (Split-Path -Path $PSScriptRoot -Parent) -Parent) -Parent
+
     # Build module if not running in psake build
     if ($null -eq $Env:BHBuildOutput) {
         # Standalone run (e.g. Invoke-Pester on this file directly, or an agent
@@ -15,12 +19,11 @@ BeforeDiscovery {
         # Invoke with & (not dot-sourcing): build.ps1 ends in an exit statement, and
         # the call operator contains it to the script boundary instead of ending the
         # whole Pester run.
-        $buildScript = Join-Path -Path (Split-Path -Path (Split-Path -Path (Split-Path -Path $PSScriptRoot -Parent) -Parent) -Parent) -ChildPath 'build.ps1'
+        $buildScript = Join-Path -Path $projectRoot -ChildPath 'build.ps1'
         & $buildScript -Task 'Build' -Bootstrap
     }
 
     # PowerShellBuild outputs to Output/<ModuleName>/<Version>/
-    $projectRoot = Split-Path -Path (Split-Path -Path (Split-Path -Path $PSScriptRoot -Parent) -Parent) -Parent
     $sourceManifest = Join-Path -Path $projectRoot -ChildPath "$Env:BHProjectName/$Env:BHProjectName.psd1"
     $moduleVersion = (Import-PowerShellDataFile $sourceManifest).ModuleVersion
     $Env:BHBuildOutput = Join-Path -Path $projectRoot -ChildPath "Output/$Env:BHProjectName/$moduleVersion"

tests/Unit/Public/Get-{{Prefix}}Example.tests.ps1

@@ -6,6 +6,10 @@
 param()
 
 BeforeDiscovery {
+    # Resolve the project root once (tests/Unit/<Layer>/ -> repo root, three levels up);
+    # used both to locate build.ps1 below and to compute the staged build output path.
+    $projectRoot = Split-Path -Path (Split-Path -Path (Split-Path -Path $PSScriptRoot -Parent) -Parent) -Parent
+
     # Build module if not running in psake build
     if ($null -eq $Env:BHBuildOutput) {
         # Standalone run (e.g. Invoke-Pester on this file directly, or an agent
@@ -15,12 +19,11 @@ BeforeDiscovery {
         # Invoke with & (not dot-sourcing): build.ps1 ends in an exit statement, and
         # the call operator contains it to the script boundary instead of ending the
         # whole Pester run.
-        $buildScript = Join-Path -Path (Split-Path -Path (Split-Path -Path (Split-Path -Path $PSScriptRoot -Parent) -Parent) -Parent) -ChildPath 'build.ps1'
+        $buildScript = Join-Path -Path $projectRoot -ChildPath 'build.ps1'
         & $buildScript -Task 'Build' -Bootstrap
     }
 
     # PowerShellBuild outputs to Output/<ModuleName>/<Version>/
-    $projectRoot = Split-Path -Path (Split-Path -Path (Split-Path -Path $PSScriptRoot -Parent) -Parent) -Parent
     $sourceManifest = Join-Path -Path $projectRoot -ChildPath "$Env:BHProjectName/$Env:BHProjectName.psd1"
     $moduleVersion = (Import-PowerShellDataFile $sourceManifest).ModuleVersion
     $Env:BHBuildOutput = Join-Path -Path $projectRoot -ChildPath "Output/$Env:BHProjectName/$moduleVersion"